there's actually a really strong lineup, i'd go day one... it's nice to see lollapalooza going back to it's roots. sonic youth imho is better when they play a shorter set. and i've never seen the flaming lips.
i also doubt that this will appeal to the high school crowd seeing as it's all "old" music... it's going to be a twentysomething and above crowd. change to lineup to trapt, three days grace, story of the year and yellowcard. then you have you have a high schooler fest...
day two confirms something pollard and i have been musing about